N=int(input())
A=list(map(int,input().split()))
if N==0:
  print('NO')
  exit()
E=[[0]*3 for i in range(3)]
E[A[2]][A[1]]=1
E[A[2]][A[3]]=1
E[A[2]][A[4]]=1
E[A[0]][A[5]]=1
for i in range(3):
  if E[i][i]==1:
    print('NO')
    exit()
  for j in range(3):
    if E[i][j]==1 and E[j][i]==1:
      print('NO')
      exit()
    if E[i][j]==1 and N<=1:
      print('NO')
      exit()
    for k in range(3):
      if E[i][j]==1 and E[j][k]==1 and E[k][i]==1:
        print('NO')
        exit()
      if E[i][j]==1 and E[j][k]==1 and N==2:
        print('NO')
        exit()
if A[0]==A[1]:
  print('YES')
  exit()
if E[A[0]][A[1]]==1:
  print('NO')
else:
  print('YES')